Stabilized polybutadiene resin

ABSTRACT

1. PROCESS OF PRODUCING A RESIN COMPOSITION HAVING A HIGH RESISTANCE TO DETERIORATION OF ITS MECHANICAL PROPERTIES UPON PROLONGED EXPOSURE TO HEAT, WHICH COMPRISES SUBJECTING TO CURING TEMPERATURES A COMPOSITION CONTAINING PARTS BY WEIGHT A BUTADIENE POLYMER OR COPOLYMER RESIN 100 A METAL DI(HYDROCARBYL)PHOSPHOUR (DI- OR TETRA- )THIOATE 0.5-5.0 A METAL SOAP 0.5-5.0 A THIAZOLE 0.25-4.0 A PEROXIDE CURING AGENT 0.5-6.0 THE RESIN BEING A HOMOPOLYMER OG BUTADIENE OR A COPOLYMER OF BUTADIENE AND STYRENE HAVING AT LEAST 80% OF THE OF BUTADIENE IN THE MOLECULE AND AT LEAST 80% OF THE BUTADIENE REPEATING UNITS IN THE RESIN BEING OF THE VINYL TYPE OF BUTDIENE; THE METAL SOAP BEING THE SOAP OF OF ABIETIC OR A FATTY ACID CONTAINING FROM 8 TO 26 CARBON ATOMS; THE PEROXIDE BEING ONE WHICH GIVES RADICALS OF THE STRUCTURE R2(CH2)CO; AND THE THIAZOLE HAVING THE FORMULA   2-R3,4-R2,5-R1-THIAZOLE   IN WHICH R1, R2 AND R3 REPRESENT HYDROGEN OR ORGANIC RADICALS WHICH MAY CONTAIN METAL CATIONS, THE ENTIRE THIAZOLE COMPOUND CONTAINING 3 TO 40 CARBON ATOMS, INCLUSIVE OF THE CARBON ATOMS IN THE THIAZOLE RING.

United States Patent 3,840,484 STABILIZED POLYBUTADIENE RESIN Delmar F. Lohr, Jr., and Edward Leo Kay, Akron, Ohio, assignors to The Firestone Tire & Rubber Company, Akron, Ohio No Drawing. Filed Nov. 13, 1972, Ser. No. 306,068 Int. Cl. C08c 11/22; C08d 9/14 US. Cl. 26023.7 M 27 Claims ABSTRACT OF THE DISCLOSURE The incorporation of a combination of a metal di(hydrocarbyl)phosphoro(dior tetra-)thioate, a metal soap and thiazole into a polybutadiene resin greatly enhances the resistance thereof to thermo-oxidative deterioration.

FIELD OF THE INVENTION This invention relates to butadiene polymers and copolymer resins, and more particularly to increasing the resistance of such resins to deterioration of the mechanical properties upon exposure to heat and air.

BACKGROUND OF THE INVENTION Butadiene polymer and copolymer resins, particularly those having, in uncured state, a high proportion of butadiene units incorporated in 1,2-configuration, have come into considerable use, particularly as electrically insulating structural components, friction elements and the like. Particularly since these resins exhibit good mechanical properties, at least initially, at high temperatures, they are attractive candidates for applications in which they will be exposed to high temperatures. At temperatures above about 600 F. (316 C.), however, the mechanical properties of these resins tend to slowly degrade over a period of time, which excludes them from many applications for which they would otherwise be very suitable. To date, however, there does not appear to have been any successful development of enhanced heat-resistant resins of this type.

Accordingly, it is an object of this invention to increase the resistance of butadiene polyber and copolymer resins to deterioration by heat and air.

Another object is to provide such heat resistant resins which will have physical and chemical properties undiminished in comparison with these resins as heretofore supplied.

A further object is to improve the heat resistance of such resins by incorporating therein modest amounts of compounding ingredients which are inexpensive and readily available, and which present no dangers or inconvenience involving toxicity, corrosiveness or the like.

SUMMARY OF THE INVENTION The above and other objects are secured, in accordance with this invention in compositions comprising:

Parts by weight Polybutadiene resin 100 A metal di(hydrocarbyl)phospho (dior tetra-) thioate 0.55.0 Ametal soap 0.55.0 A thiazole 0.5-5.0

3,840,484 Patented Oct. 8, 1974 DESCRIPTION OF THE PREFERRED EMBODIMENTS The polybutadiene resins These may be any resins which are based on polymers of butadiene or copolymers of butadiene with up to 60%, based on the copolymers, of styrene. Also minor proportions, say up to 15% based on the copolymer of other ethylenically unsaturated compounds may be incorporated in the copolymers. These resins are usually prepared by (co) polymerizing the monomers by means of free radical or anionic catalysts to a relatively low molecular weight,

say 1000-200,000, so that they are of at least a flowable consistence. These low molecular weight (co)polymers are then incorporated with any desired fillers, reinforcing fibers or fabrics, pigments, etc., peroxide or other curing agents if desired, etc., and the composite is cured under heat and pressure to produce the desired finished article.

More particularly, there have recently been developed a class of polybutadiene resins having at least 40%, and preferably at least 60% by weight, of butadiene in the polymer molecule, and having at least by weight of the butadiene therein in the vinyl type of butadiene repeating unit structure. The average molecular weight (determined by intrinsic viscosity measurement) is at least 12,500 and the molecular weight distribution is such that at least 50%, and preferably of the polymer has a molecular weight above 10,000 and at least has a molecular weight above 2,000. It has been found that the of higher proportions of lower molecular weight polymers than allowed by these limitations causes slow curing rates and poor physical properties in the cured product. For good processibility and good flow during molding the average molecular weight should be no greater than 55,000. This corresponds to an intrinsic viscosity of about 0.7 taken at 25 C. or about 0.68 taken at 30 C. The resin should also have a dilute solution viscosity of 0.2- 0.7, preferably 0.3-0.6. The butadiene units are incorporated into the polymeric chain largely in the 1,2-configuration, preferably at least 80% of the butadiene units pres ent being in this configuration. These polymers are cured by incorporating, per parts of polymer, approximately 0.5-6 parts, and preferably 1.5-3.0 parts, by weight of dicumyl peroxide (or an equivalent weight of any other peroxide giving radicals of the structure R (CH )CO-, where R independently in each occurrence represents a hydrocarbon radical of 1-20 carbon atoms), and heating the polymers, usually under pressure. The curing temperature is advantageously at least 250 F. (121 C.), preferably about 300-350 F. (149-177 C.). Generally, no advantage in the process or product is obtained by exceeding a temperature of 420 F. (216 C.). Obviously, the higher the temperature the shorter will be the curing time required. Generally at 350 F. (177 C.) a satisfactory cure is obtained in less than four minutes, and in some cases even within a few seconds. Cure times of more than four minutes usually provide no added advantage. Where fast cures are desired it is necessary to use a filler to avoid crazing or cracking. A filler, such as silica, is advantageously used in the proportion of 25-65, preferably 40- 60, volume percent based on the combined'resin-filler composition. Also the resins may be incorporated with glass fiber, either as chopped filler or else as glass fabric in a laminate, in which case the glass fiber will serve the purpose of a filler in preventing crazing and cracking on fast cures.

More particularly with regard to the inclusion of fillers, the present invention is of particular advantage in the stabilization of compositions containing silica fillers inamounts of to 500 parts by weight per 100 parts by weight of butadiene polymer or copolymer. In such cases 3 it is desirable to include 0.5 to 2.0 parts per 100 parts of silica of an agent for bonding the filler to the olybutadiene resin such as an unsaturated-group-containing silane on the order of vinyl triacetoxysilane vinyl tributoxy silane, vinyl trimethoxysilane, and vinyl triethoxysilane.

The metal soap This may be any metal salt and preferably a Group II-A or II-B metal salt (see Handbook of Chemistry and Physics, 43rd ed., The Chemical Rubber Publishing Co., 1961, pages 448 and 449) of a higher fatty acid containing from 8 to 26 carbon atoms such as calcium 2-ethylhexanoate, calcium octoate, calcium laurate, calcium myristate, calcium stearate, calcium palmitate, calcium oleate, calcium arachidate, calcium abietate, magnesium stearate, magnesium octoate, magnesium oleate, zinc stearate, zinc oleate, zinc laurate, zinc abietate, cadmium stearate, and the like, and mixtures of any two or more of such salts in any proportions.

The metal di(hydrocarbyl)phosphoro (dior tetra-) thioates R, independently in each occurrence, is a hydrocarbyl radical containing l-25 carbon atoms M is a polyvalent metal, preferably zinc or cadmium n=the valence of the metal M indicates either oxygen (in the case of dithioates) or sulfur (in the case of tetrathioates) bridging R and P and the remainder of the formula follows conventional chemical notation.

where Examples of hydrocarbyl radicals which may occupy the situation indicated at R in Formula I are simple aliphatic hydrocarbon radicals such as ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, Z-ethylhexyl, n-dodecyl, the mixed radicals derived from petroleum fractions or the reduction of natural fatty glycerides such as coconut oil or tallow, cycloaliphatic radicals such as cyclohexyl, methylcyclohexyl, the reduction products of naval stores, aromatic radicals such as phenyl, pand m-toluyl, naphthyl and aralkyl radicals such as benzyl, phenylethyl and the like. Metals which form the component M in Formula I may be any dior trivalent metals, particularly those of Group II-B and Groups VIII of the Periodic Chart of the Elements (Handbook of Chemistry and Physics, 43rd ed., The Chemical Rubber Publishing Co., 1961, pages 448 and 449), and particularly zinc, cadmium, copper, manganese, cobalt, iron and nickel. Specific suitable compounds include, for instance, zinc diisopropylphosphorodithioate, cadmium diisopropylphosphorodithioate, zinc di- (sec-butyl)phosphorodithioate, zinc diisobutylphosphorodithioate, cadmium diisobutylphosphorodithioate, zinc di- (cyclohexyl)phosphorodithioate, cadmium di(o-toluyl) phosphorodithioate, zinc dibenzylphosphorodithioate, zinc di(Z-ethylhexyl)phospborotetrathioate, zinc di(1,3-dimethylbutyl)phosphorodithioate, Cu (1,3 dimethylbutyl) phosphorodithioate, Mn (1,3-dimethylbutyl)phosphorodithioate, Co 1,3 dimethylbutyl)phosphorodithioate, Fe (1,3-dimethylbutyl)phosphorodithioate, Ni (1,3-dimethylbutyl)phosphorodithioate, and the like.

The thiazole This may be any compound containing the thiazole ring where the R R and R independently in each occurrence represent hydrogen or attachments to organic radicals, the entire compound containing from 3 to 40 carbon atoms, inclusive of the carbon atoms in the thiazole ring.

It has been discovered that benzothiazole derivatives are particularly eifective and are the preferred compounds. Exemplary thiazoles are Z-mercaptobenzothiazole and metal salts of 2-mercaptobenzothiazole such as Zn, Cd, Ni, Cu, Mn, Co, Fe, etc., 2,2-dithiobis(benzothiazole) as well as N-substituted-hydrocarbyl 2 benzothiazole sulfenamides Where the hydrocarbyl radical may be simple aliphatic hydrocarbon radicals such as methyl, ethyl, npropyl, isopropyl, n-butyl, isobutyl, t-butyl, etc., cycloaliphatic radicals such as cyclopentyl, cyclohexyl, methylcyclohexyl, etc., aromatic radicals such as phenyl, 0-, m-, p-tolyl, etc., and aralkyl radicals such as benzyl, phenylethyl and the like, N,N-disubstituted-hydrocarbyl-Z-ben- Zothiazolesulfenamides should also be effective in which the hydrocarbyl radicals are defined herein. Sulfenamides prepared with compounds in which the amine function is in a hydrocarbyl ring should also be effective. For example, 2- (morpholinothio benzothiazole, 2- (piperidinothio)benzothiazole, 2 (pyrrolindinothio)benzothiazole, etc.

The cured resins The cured resins produced in accordance with this invention have exceptional resistance to deterioration of physical properties, particularly modulus and flexural strength, upon long time exposure at high temperatures, i.e., temperatures above 400 F. and up to 700 F. Thus, the products, upon exposure to temperatures of 400 F. for 1000 hours, or 600 F. for hours, will retain upwards of 80% of their modulus and upwards of 60% of their fiexural strength. The resins are therefore applicable in many situations where heat exposure is a factor, as in structural electrical components, cooking utensil handles, and automobile engine compartment components.

With the foregoing general discussion in mind, there are given herewith detailed experimental examples of the practice of this invention. All parts and percentages given are 3n the basis of weight, unless otherwise explicitly state waiit' zfr miliii ifw355063 ii':"23 66 i%=5.%

2 Per Table I. i

A series of compositions was made up in accordance with the above schedule, varying the metal soap, phosphoro-(dior tetra-)thioate and thiazole in the several compositions as indicated in Table I. In the case of each composition, all of the ingredients, in the proportions selected for that composition, were thoroughly mixed together, and the mixture poured into an evaporating dish to the depth of about 0.5 inch. The dish was then placed in a vacuum oven, Where the hexane was removed at F. under a pressure of 1-5 mm. of mercury 1 5 Am .5 com 6A AA cm A I I n mA 00 I. 80 2 II A 0080000 M 00 A II S 00 80 Q: 00 A I 83 on 2 2 0 0 330 02 1 8 Am IIIII IIIIII II 00A AA II A 11703090005 3 8A 8A 2 ANA 0A A 0800 on 8 EA0 0 0 522 200 0 N 00 8A 6 II AN A %00000 -282 53 030000 0 mm I awoaxm dw 0 000N00 on 0 SQ OE QSSE 0 00 A hm A00m000m M on ma 008002 2325803 030000 0m 8 MM mwmmmwwww 2 0 0 0 00 mm I EmRAx W I AAAM IIA00m0ax00DI A A AA Q A N N 00 A I 00003000000000000003500000 0 MM IIIIIIII 2325303 Ao fl osA cA eoaYm A on o co m 3 00 A: 00 Q A I 8 0 3 0 MM A W IIIIIII II com NA IIIIIIIIII II AA A IIII c wA D. IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII I IAI000Z 80 0A 8A 0A A I 0 x I. IIIIIIIIII II 0 IIIIIIIIII II m A IIII 00000000 00 o 20003000000300.0350 0N IIIIIII I 00025: 000A nAm000 0000 0 0 d 0 NA cm 00 0 S 2 A I A 0 AA IIIIIIIIII I. 000 AA IIIIIIIIII II Am A II 1600000805 IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII 02 8 A MA mm cow AA mm mm A IIIIII I A w mAw co m IIIIIIIIII I. 00 A IIIIIIIIIIII 00 030 000 IIIIIIIIIIII.IIIIIIIIII.IIIII.IIIIII.III.III-0002 0 BA 00A AA woA E A IIIIII I A 80 IIIIIIIIIIIII .I I 00 IIIIIIIIIIIIIIIIIIII 005020 000200 I IIIIIIIII II 03 IIIIIIIIII II Q A IIII 500000? on 0 20202303800205 A 0N 00500500000000003300 00v 0 0 mm cow Hm mm mm A IIIIII I I A GAM n IIIIIIIIII II :2 QA IIIIIIIIII II mm A IIII 1000000005 IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII II 2 so A A mm 20 m 8 8 o 8 0 m IIIIIIIIII I. m A IIII vwmonx p IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII 0002 II... 0002 0 IIIIII I.

A .0 A; .0 Ax 0 Z 00500000 dd 00500000 I X 0.500000 m mm 09A 300m 0005 A000: 09a. 00m 000200 0083 20 .00 000 0.2mm

I|IIIII|IIIII Illlllll 0 2820 302000208 00088000805 00 035 25 0 030A 05 500 0 0000000 0953 000 00 0000 2 @5000 0 020000000 33930 0 0000200 000mm. 0 00m: 0 000 020N030 000 0 0052-003 00 EQSA AAS A @3000 QA EV U 0 0023050000 050 00 00250 2 AA 330 m 0000 $2 3 5000 3 0 003:080008003502050? 0 0 2000 oo A B 000005000 5 232500000 A Q QA EQEV 0 0 0 0000500 05 05 5:05 0m 000 mm 002 0000 00 0 000000 000 w wm .A0 0 00300000 A w00 w EEA 000 0200000 00 0 0N0 A 0N00 0 00000E 0 mm 00 0 0 0000 00.000 05 23 00000 000 200250000 A03 Q0 0AI E0EV 05 B000 m @000: R 002 003 0300300 00003 woAAmAboo m 0 A0 0 0 A w A 2020200 0 0500 000 30000000 000 0 00000 00 5000. 0 258 000 2 0 000 000000 @00 0 0N0 0 0N00h 0 0000000 0 0 000 om 0 0000800 0% 6m 000 mm 002 m5: 3 030 0 2 0 0000 00000000000000 0 0:3 0000030000 0 20505303 OASBE 0 0 00 0 00 000n 05 8 205 000mm 0m 00 0005 AN 0000 0 00000000 00% 05 0 00w 000A000 0 0000 0 00 0 0020 0 0000 0 00N000 0 0m @0000: AN 002 0000 E 5 0 00 3 20000 AA GN MN 2 mA AA0N00nA0 nA0000E 0 003 080% 0 00 0 E E w A 0003 30.00 mi-00c 000 0300000 EES 0000000 05 85095 00005 00 200080238 I 0 I 0 0 0 3000 QNIQA 00 5000 0200000000 0 0 2002 836560 1 5 A 0 02 A 00 3 200 5 00 \3 00 00A-0 00m A w00 m 000 0300000 0000000 000m 6A @0005 AA 002 0000 00 0 05 3 03000 020 0 0 0N A 0N00 Q 0IA0E 0 0 00 0 02000000 00 00 00 0 000 0 3: 0 0% 0 5 000000 000 20000 0000000000 00 0 00 Am 000 b 002 0003 0200000 000000 05 0 05 00 0 00 0 0000 00A w ww 00 0 000 50 w00 0 0%025 000 0300000 2360 0 0030005 300000 0 0N0 0N00n0 0000000 0 0 03 om 0 0020 05 000000000 B A0 000 m 002 0003 20330030 mw 000 00 0 30300000 0%0005 000 0200000 020000 000 00000005 00 20000 0 E 00 -0500000A AAm0A 0 0o 0 0 0 A0 000 ooA 0 020305 0A A 0 A 00AAw00 0mm 000 @mm A A w00 m 000 0300000 S0000 0 00 00 00 000000 600 0000 05 0305 m 000000 00 0 005 0 00 000320 00. w 0950.: A 005 0:080 05 000 A 0 0% 0 00 00m 03098 0000 00 05 :3 A 030 E 00 000 00 020 000 00502 0 0&023 EEE 000 0500000 05 000 200 0 00 000 0 00 0 .00 00 5 0000000 0003 020009000 0000 0 005 0050 0002000000 000 8 0000000 00 0003 00 0000 00 0 00:0: 0 0800 0000 000 00 05 003 A 030 0 0000000 0000050 05 000 0 0000000 0000 050 200 0000. 0000 000 0 0 00 003 53000 SES 000 0000000 00 0000500 000 008 0E0 000 000 m x :A 0 0 0 0000 000 o 3B 0 00 00 002 A88 m 0mm 090 053000 0 000 0.000000 0038 0 0 000 00 .005 0000000000 05 0 30200005 0050 05 0:3 00 003 000 :08 0 8 00 000 00 000 5000 05 303 0000 3 o x m x :A 905 000 000 $3 0 205 02000000000 0 E 002000 000 00 00x05 000 0050000 005 00? 000 000000 00 0000 00mm What is claimed is: 1. Process of producing a resin composition having a high resistance to deterioration of its mechanical properties upon prolonged exposure to heat, which comprises subjecting to curing temperatures a composition containing Parts by weight A butadiene polymer or copolymer resin 100 A metal di(hydrocarbyl)phosphoro (dior tetra-)thioate 0.55.0 A metal soap (LS-5.0 A thiazole O.254.0 A peroxide curing agent 0.5-6.0

the resin being a homopolymer of butadiene or a copolymer of butadiene and styrene having at least 40% of butadiene in the molecule and at least 80% of the butadiene repeating units in the resin being of the vinyl type of butadiene; the metal soap being the soap of abietic or a fatty acid containing from 8 to 26 carbon atoms; :the peroxide being one which gives radicals of the structure R (CH )CO-; and the thiazole having the formula R1 /S /Rs in which R R and R represent hydrogen or organic radicals which may contain metal cations, the entire thiazole compound containing 3 to 40 carbon atoms, inclusive of the carbon atoms in the thiazole ring.

2. Process according to claim 1, wherein the composition further contains, by weight A silica filler l50500 (per 100 parts of resin).

A silane bonding agent 0.52.0 (per 100 parts of silica filler).

3. Process according to claim 1, wherein the metal soap is calcium stearate.

4. Process according to claim 1 wherein the thiazole is zinc Z-(mercapto)benzothiazole.

5. 'Process according to claim 1 wherein the thiazole is 2-(morpholinothio)mercaptobenzothiazole.

6. Process according to claim 1, wherein the peroxide curing agent is dicumyl peroxide.

7. Process according to claim 1, wherein proportions of metal di(hydrocarbyl)phosphoro(dior tetra-)thioate, metal soap and thiazole are more particularly Parts by weight Metal di-(hydrocarbyl)phosphoro (dior tetra-) thioate 1.0-3.0

Metal soap 2.0-4.0 Thiazole 0.50-2.5

8. Process according to claim 7, wherein the peroxide curing agent is dicumyl peroxide.

9. Process according to claim 1, wherein the met-a1 component of the, .metal di(hydrocarbyl)phosphoro (dior tetra-)thioate is zinc.

10. A composition curable to a hard resin composition having enhanced resistance to deterioration of its mechanical properties by exposure to heat and air comprising Parts by weight A butadiene polymer or copolymer resin 100 A metal di(hydrocarbyl)phosphoro (dior tetra-)thioate 0.55.0

A metal soap O.5-5.0

A thiazole 0.25-4.0

A peroxide curing agent 0.56.0

the resin being a homopolymer of butadiene or a copolymer of butadiene and styrene having at least 40% of butadiene in the molecule and at least 80% of the butadiene repeating units in the resin being of the vinyl type of butadiene; the metal soap being the soap of abietic or a fatty acid containing from 8 to 26 carbon atoms; the peroxide being one which gives radicals of the structure R (CH )CO'; and the thiazole having the formula in which R R and R represent hydrogen or organic radicals which may contain metal cations, the entire thiazole compound containing 3 to 40 carbon atoms,,inclusive of the car-hon atoms in the thiazole ring.

11. A composition according to claim 10 which further contains, by weight A silica filler 150 parts (per 100 parts of resin). A siliane bonding agent 0.5-200 parts (per 100 parts of silica filler).

thioate 1.03.0 Metal soap 2.0-4.0 Thiazole 0.52.5

17. Composition according to claim 16, wherein the peroxide is dicum'yl peroxide.

18. Composition according to claim 10, wherein the metal component of the metal di(hydrocarbyDphosphoro- (dior tetra-)thioate is zinc.

19. A peroxide-cured resin composition highly resistant to deterioration of physical properties upon exposure to heat, said resin containing therein Parts by weight A butadiene polymer or copolymer resin 100 A metal di(hydrocarbyl)phosphoro (dior tetra) thioate 0.5-5 .0 A metal soap 0.55.0 A thiazole 0.254.0

the resin being a homopolymer of butadiene or a copolymer of butadiene and styrene having at least 40% of butadiene in the molecule and at least of the butadiene repeating units in the resin being of the vinyl type of butadiene; the metal soap being the soap of abietic acid or a fatty acid containing from 8 to 26 carbon atoms; having the formula in which R R and R represent hydrogen or organic radicals which may contain metal cations, the entire thiazole compound containing 3 to 40 carbon atoms, inclusive of the carbon atoms in the thiazole ring.

20. Cured resin according to claim 19 which further contains, by weight A silica filler 150500 parts (per 100 parts of resin).

A Silane bonding agent 0.52.0 parts (per 100 5 or tetra parts of silica filler).

26. Cured resin according to claim 25, wherein the peroxide is dicumyl peroxide.

27. Cured resin according to claim 19, wherein the metal component of the di(hydrocarbyl)phosphoro(di- )th=ioate is zinc.

References Cited UNITED STATES PATENTS 3,494,900 2/1970 Morita 260--23.7 M 3,196,134 7/1965 Donat 26087.1 3,511,795 5/1970 Brodie 26023.7 3,408,253 10/1968 Eckert 161-253 3,156,666 11/1964 Pruett 26041 A 2,906,731 9/1959 Hill et al. 260-45.7 PS 3,317,446 5/ 1967 Wilder 26027 BB DONALD E. CZAJA, 'Primary Examiner W. E. PARKER, Assistant Examiner U.S. Cl. X.R.

260-27 BB, 41 A, 45.7 PS

Invntofls) Delmar 11. Lohtc, Jr. and Ed rdjLeQ- a and that: said Letters Patent are hereby corrected as "sh'wn below:

' Atqesting Officer v UNITED STATES PATEN'Ii OFEI CEf- CERTIFICATE OF-GORRJEGIjI-ON )1- Dated 97 I It is certified that er rora ppearsi n tha abdvg ideptified.pafint In Column. 1, Line +2, "polyber" should. vpol yrn'ezv: I

In Column 6, Tabl 'e l, wmder Thiazol e Line 8, "Nbne -L" should be nonev r In Column '9, Claim 24, Line 2, xii-n9shisimrbe 'l'i' Signed ahd seaied this lltfidiy; of

(SEAL) Attest:

C. MARSHALL DANN Com i'as ibner of Bartgnt and Trademarkq Rum/c. MASON 

1. PROCESS OF PRODUCING A RESIN COMPOSITION HAVING A HIGH RESISTANCE TO DETERIORATION OF ITS MECHANICAL PROPERTIES UPON PROLONGED EXPOSURE TO HEAT, WHICH COMPRISES SUBJECTING TO CURING TEMPERATURES A COMPOSITION CONTAINING PARTS BY WEIGHT A BUTADIENE POLYMER OR COPOLYMER RESIN 100 A METAL DI(HYDROCARBYL)PHOSPHOUR (DI- OR TETRA- )THIOATE 0.5-5.0 A METAL SOAP 0.5-5.0 A THIAZOLE 0.25-4.0 A PEROXIDE CURING AGENT 0.5-6.0 THE RESIN BEING A HOMOPOLYMER OG BUTADIENE OR A COPOLYMER OF BUTADIENE AND STYRENE HAVING AT LEAST 80% OF THE OF BUTADIENE IN THE MOLECULE AND AT LEAST 80% OF THE BUTADIENE REPEATING UNITS IN THE RESIN BEING OF THE VINYL TYPE OF BUTDIENE; THE METAL SOAP BEING THE SOAP OF OF ABIETIC OR A FATTY ACID CONTAINING FROM 8 TO 26 CARBON ATOMS; THE PEROXIDE BEING ONE WHICH GIVES RADICALS OF THE STRUCTURE R2(CH2)CO; AND THE THIAZOLE HAVING THE FORMULA 